Revert "powerpc/64s: Remove PROT_SAO support"

This reverts commit 5c9fa16e8a.

Since PROT_SAO can still be useful for certain classes of software,
reintroduce it. Concerns about guest migration for LPARs using SAO
will be addressed next.

Signed-off-by: Shawn Anastasio <shawn@anastas.io>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200821185558.35561-2-shawn@anastas.io
This commit is contained in:
Shawn Anastasio 2020-08-21 13:55:56 -05:00 committed by Michael Ellerman
parent 64ef8f2c47
commit 12564485ed
13 changed files with 90 additions and 17 deletions

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@ -20,13 +20,9 @@
#define _PAGE_RW (_PAGE_READ | _PAGE_WRITE)
#define _PAGE_RWX (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)
#define _PAGE_PRIVILEGED 0x00008 /* kernel access only */
#define _PAGE_CACHE_CTL 0x00030 /* Bits for the folowing cache modes */
/* No bits set is normal cacheable memory */
/* 0x00010 unused, is SAO bit on radix POWER9 */
#define _PAGE_SAO 0x00010 /* Strong access order */
#define _PAGE_NON_IDEMPOTENT 0x00020 /* non idempotent memory */
#define _PAGE_TOLERANT 0x00030 /* tolerant memory, cache inhibited */
#define _PAGE_DIRTY 0x00080 /* C: page changed */
#define _PAGE_ACCESSED 0x00100 /* R: page referenced */
/*
@ -828,6 +824,8 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
return hash__set_pte_at(mm, addr, ptep, pte, percpu);
}
#define _PAGE_CACHE_CTL (_PAGE_SAO | _PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
#define pgprot_noncached pgprot_noncached
static inline pgprot_t pgprot_noncached(pgprot_t prot)
{

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@ -196,7 +196,7 @@ static inline void cpu_feature_keys_init(void) { }
#define CPU_FTR_SPURR LONG_ASM_CONST(0x0000000001000000)
#define CPU_FTR_DSCR LONG_ASM_CONST(0x0000000002000000)
#define CPU_FTR_VSX LONG_ASM_CONST(0x0000000004000000)
// Free LONG_ASM_CONST(0x0000000008000000)
#define CPU_FTR_SAO LONG_ASM_CONST(0x0000000008000000)
#define CPU_FTR_CP_USE_DCBTZ LONG_ASM_CONST(0x0000000010000000)
#define CPU_FTR_UNALIGNED_LD_STD LONG_ASM_CONST(0x0000000020000000)
#define CPU_FTR_ASYM_SMT LONG_ASM_CONST(0x0000000040000000)
@ -441,7 +441,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
CPU_FTR_DSCR | CPU_FTR_ASYM_SMT | \
CPU_FTR_DSCR | CPU_FTR_SAO | CPU_FTR_ASYM_SMT | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | \
CPU_FTR_VMX_COPY | CPU_FTR_HAS_PPR | CPU_FTR_DABRX )
@ -450,7 +450,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
CPU_FTR_DSCR | \
CPU_FTR_DSCR | CPU_FTR_SAO | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_DAWR | \
@ -461,7 +461,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
CPU_FTR_DSCR | \
CPU_FTR_DSCR | CPU_FTR_SAO | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
@ -479,7 +479,7 @@ static inline void cpu_feature_keys_init(void) { }
CPU_FTR_MMCRA | CPU_FTR_SMT | \
CPU_FTR_COHERENT_ICACHE | \
CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
CPU_FTR_DSCR | \
CPU_FTR_DSCR | CPU_FTR_SAO | \
CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \

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@ -13,20 +13,38 @@
#include <linux/pkeys.h>
#include <asm/cpu_has_feature.h>
#ifdef CONFIG_PPC_MEM_KEYS
static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
unsigned long pkey)
{
return pkey_to_vmflag_bits(pkey);
#ifdef CONFIG_PPC_MEM_KEYS
return (((prot & PROT_SAO) ? VM_SAO : 0) | pkey_to_vmflag_bits(pkey));
#else
return ((prot & PROT_SAO) ? VM_SAO : 0);
#endif
}
#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
{
return __pgprot(vmflag_to_pte_pkey_bits(vm_flags));
#ifdef CONFIG_PPC_MEM_KEYS
return (vm_flags & VM_SAO) ?
__pgprot(_PAGE_SAO | vmflag_to_pte_pkey_bits(vm_flags)) :
__pgprot(0 | vmflag_to_pte_pkey_bits(vm_flags));
#else
return (vm_flags & VM_SAO) ? __pgprot(_PAGE_SAO) : __pgprot(0);
#endif
}
#define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags)
#endif
static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
{
if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM | PROT_SAO))
return false;
if ((prot & PROT_SAO) && !cpu_has_feature(CPU_FTR_SAO))
return false;
return true;
}
#define arch_validate_prot arch_validate_prot
#endif /* CONFIG_PPC64 */
#endif /* _ASM_POWERPC_MMAN_H */

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@ -82,6 +82,8 @@
*/
#include <asm/nohash/pte-book3e.h>
#define _PAGE_SAO 0
#define PTE_RPN_MASK (~((1UL << PTE_RPN_SHIFT) - 1))
/*

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@ -11,7 +11,7 @@
#include <asm-generic/mman-common.h>
#define PROT_SAO 0x10 /* Unsupported since v5.9 */
#define PROT_SAO 0x10 /* Strong Access Ordering */
#define MAP_RENAME MAP_ANONYMOUS /* In SunOS terminology */
#define MAP_NORESERVE 0x40 /* don't reserve swap pages */

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@ -653,7 +653,7 @@ static struct dt_cpu_feature_match __initdata
{"processor-control-facility-v3", feat_enable_dbell, CPU_FTR_DBELL},
{"processor-utilization-of-resources-register", feat_enable_purr, 0},
{"no-execute", feat_enable, 0},
/* strong-access-ordering is unused */
{"strong-access-ordering", feat_enable, CPU_FTR_SAO},
{"cache-inhibited-large-page", feat_enable_large_ci, 0},
{"coprocessor-icswx", feat_enable, 0},
{"hypervisor-virtualization-interrupt", feat_enable_hvi, 0},

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@ -232,6 +232,8 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
rflags |= HPTE_R_I;
else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_NON_IDEMPOTENT)
rflags |= (HPTE_R_I | HPTE_R_G);
else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_SAO)
rflags |= (HPTE_R_W | HPTE_R_I | HPTE_R_M);
else
/*
* Add memory coherence if cache inhibited is not set

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@ -321,6 +321,8 @@ extern unsigned int kobjsize(const void *objp);
#if defined(CONFIG_X86)
# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */
#elif defined(CONFIG_PPC)
# define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */
#elif defined(CONFIG_PARISC)
# define VM_GROWSUP VM_ARCH_1
#elif defined(CONFIG_IA64)

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@ -114,6 +114,8 @@ IF_HAVE_PG_IDLE(PG_idle, "idle" )
#if defined(CONFIG_X86)
#define __VM_ARCH_SPECIFIC_1 {VM_PAT, "pat" }
#elif defined(CONFIG_PPC)
#define __VM_ARCH_SPECIFIC_1 {VM_SAO, "sao" }
#elif defined(CONFIG_PARISC) || defined(CONFIG_IA64)
#define __VM_ARCH_SPECIFIC_1 {VM_GROWSUP, "growsup" }
#elif !defined(CONFIG_MMU)

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@ -2453,6 +2453,10 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
if (vma_is_dax(vma))
return 0;
#ifdef VM_SAO
if (*vm_flags & VM_SAO)
return 0;
#endif
#ifdef VM_SPARC_ADI
if (*vm_flags & VM_SPARC_ADI)
return 0;

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@ -2,6 +2,7 @@
hugetlb_vs_thp_test
subpage_prot
tempfile
prot_sao
segv_errors
wild_bctr
large_vm_fork_separation

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@ -2,7 +2,7 @@
noarg:
$(MAKE) -C ../
TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot segv_errors wild_bctr \
TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot prot_sao segv_errors wild_bctr \
large_vm_fork_separation bad_accesses pkey_exec_prot \
pkey_siginfo stack_expansion_signal stack_expansion_ldst
@ -14,6 +14,8 @@ include ../../lib.mk
$(TEST_GEN_PROGS): ../harness.c ../utils.c
$(OUTPUT)/prot_sao: ../utils.c
$(OUTPUT)/wild_bctr: CFLAGS += -m64
$(OUTPUT)/large_vm_fork_separation: CFLAGS += -m64
$(OUTPUT)/bad_accesses: CFLAGS += -m64

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@ -0,0 +1,42 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2016, Michael Ellerman, IBM Corp.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <asm/cputable.h>
#include "utils.h"
#define SIZE (64 * 1024)
int test_prot_sao(void)
{
char *p;
/* 2.06 or later should support SAO */
SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06));
/*
* Ensure we can ask for PROT_SAO.
* We can't really verify that it does the right thing, but at least we
* confirm the kernel will accept it.
*/
p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE | PROT_SAO,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
FAIL_IF(p == MAP_FAILED);
/* Write to the mapping, to at least cause a fault */
memset(p, 0xaa, SIZE);
return 0;
}
int main(void)
{
return test_harness(test_prot_sao, "prot-sao");
}